Investigations of the etiology of adult periodontal disease have focused on the microorganism Bacteroides gingivalis. Efforts are underway to determine the nature of this suspected periodontal pathogen's virulence factors and to identify the organism's major antigens. Numerous investigators are attempting to clone Bacteroides genes. We propose to examine the DNA of B. gingivalis by pulsed filed electrophoresis. This will enable us to: 1) Determine an accurate size of the chromosome, which is essential information for construction of complete gene banks. 2. Make a comparison of restriction fragment length polymorphism, which will allow an estimate of the genetic diversity which exists within the species. 3. Identify large or linear plasmids that can not be isolated by CsC1 gradient centrifugation or detected on conventional agarose gels. 4. Construct a restriction map of the B. gingivalis genome, which will serve as a foundation for the further genetic study of this microorganism.